The disclosure provides an apparatus and method for setting antennas of a mobile device, and a mobile device, and the apparatus includes: one or more processors; and a memory, where the memory is configured to store one or more computer readable program codes, and the one or more processors are configured to execute the one or more computer readable program codes to perform operations of: functioning, by the mobile device, as a Wi-Fi relay to be connected with both a wireless access point and an electronic device, wherein the mobile device is provided with at least two Wi-Fi antennas to receive and transmit Wi-Fi data; determining a communication type of communication between the wireless access point and the electronic device; and adjusting the number of receiving antennas and the number of transmitting antennas among the Wi-Fi antennas according to the communication type.